1. Field of the Instant Disclosure
The instant disclosure relates to a semiconductor device; in particular, to a method of forming an isolation area on the semiconductor and a structure thereof.
2. Description of Related Art
In recent years, along with the advance of technology in the field of the semiconductor integrated circuit manufacturing, the amount of components contained within each chip has increased significantly. However, the size of the chips has not grown consequently larger, in fact, smaller even with the rise of the component density in the chips. Furthermore, the width of the circuits has also advanced to grow smaller from micron to far smaller sizes. Nevertheless, regardless of how small a chip can be, all components within each chip have to be isolated or insulated appropriately before a fine quality can be achieved. Generally, the device isolation technology is adapted for isolation of the components. To provide further explanations, isolating barriers are formed between the components and the area/space occupied by the isolating barriers is minimized in every possibility under the condition of providing a good insulating effect. Thus, more chip areas can be provided for occupation of more components.
Among various device isolation technologies, the local oxidation of silicon (LOCOS) and the shallow trench isolation (STI) technologies are most adapted in the process of manufacturing. Particularly, the technology of STI has advantages such as a smaller area utilized for isolation, and the capability of maintaining a flat substrate after processing. Therefore, the STI technology has earned its popularity in the field of semiconductor manufacturing technology. However, with the development of the burying structure (such as burying the components within the chips), the word lines are then formed in the trenches. Therefore, the fine insulating effect provided by the STI technology will enable the word line trenches and the STI trenches to obtain different depths. Thus, at least two photo masks are required for manufacture of the aforementioned word line trenches and the STI trenches, and thereby increasing the complexity in production.